The Histopathology (Histology) section of the Laboratory of Pathology (LP) is a core facility devoted to supporting the clinical activities of LP. The laboratory processes a large variety of tissue specimens from NIH and non-NIH patients, including a wide variety of malignancies, AIDS-related diagnostic specimen, infections, and surveillance biopsies. This consists of accessioning human tissues removed at surgery or in clinics, processing the tissues, preparing and staining slides for microscopy by LP's pathologists, clinical fellows and residents. Pathology residents are trained by LP's Pathologists Assistants (PAs) in techniques of gross dissection and learn to evaluate large and small specimens in preparation for microscopic evaluation during Histology rotations. The Histology lab serves the Surgical Pathology, Hematopathology, Postmortem Pathology and Cytopathology sections as well as the Specialized / Molecular Diagnostics Unit. To date during this fiscal year through July, approximately 26,000 tissue blocks were prepared and over 172,000 slides were cut from inhouse biopsy and surgical cases. During this period, LP's Pathologists Assistants performed and trained residents in gross analysis and selection of the most diagnostic sections for tissues collected from over 2,600 inhouse biopsy and surgical tissues. Over 53,000 special stains were performed in Histology and approximately 24,000 stains in Immunohistochemistry from inhouse and submitted cases. At the current rate, Histology is projected to cut about 230,000 slides and perform 115,500 special and IHC stains for the full fiscal year. The lab also processes slides and blocks submitted from outside laboratories for NIH or non-NIH patients. So far this fiscal year, the laboratory processed processed over 93,000 consult slides and 2,500 blocks from over 2,100 cases that were submitted to LP's pathologists for clinical consultation or review for patients being admitted to the NIH Clinical Center or entry on protocol. Although more than 95% of effort is devoted to clinical duties, the Histology Laboratory also performs recuts of tissue blocks and does some routine staining for research projects in NCI by arrangement. This activity is coordinated with the tissue research request function of Clinical Operations. For this fiscal year, more than 8,500 unstained and stained slides and more than 150 tissue shaving tubes, recut from more than 1,600 ffpe tissue blocks, were prepared and issued to investigators NIH-wide. The Histology Lab does not conduct primary research but supports the activities of many investigators.